The present invention relates to solenoid valve harnesses for use in hydraulic transmissions of vehicles.
Hydraulic transmissions of vehicles, such as automobiles or trucks, include a transmission valve body which is located inside the transmission case. The transmission valve body houses spool valves which direct oil flow for operating clutches of the transmission and for pressure regulation. The spool valves located inside the transmission valve body are operated by smaller solenoid valves that are mounted on the transmission valve body. These solenoid valves are operated by a microprocessor controller that is located outside the transmission case. The microprocessor controller provides signals to the solenoid valves which in turn operate the larger spool valves inside the transmission valve body which in turn operate the clutches and the pressure regulator. Alternatively, the solenoid valves may operate the clutches directly.
In one conventional arrangement of a vehicle transmission, there are four solenoid valves. These solenoid valves may be similar or identical to the solenoid valves described in U.S. Pat. No. 5,322,260. These solenoid valves are located inside the vehicle transmission case and are mounted on the transmission valve body. A wiring harness connects to each of these solenoid valves in order to convey electrical signals from the vehicle microprocessor controller which is located outside the transmission case.
In the solenoid valve, the magnet wire used for the solenoid coil is relatively small and fragile compared to the wires used for the harness. In typical prior solenoid valve harnesses, the solenoid valve coil wires are connected to the wires of the harness by soldering or welding. Due to the small size of the coil wires and coil region, this process can be relatively labor intensive, and therefore costly. In addition, the solenoid valve wiring harness is subject to stresses, such as tensile and torsional, during later stages of manufacture and during operation. Because of the difference in size between the solenoid coil wires and the wires of the harness, the connection between the harness and the solenoid valves is susceptible to damage. If just one of the solenoid valve coil wire connections is faulty, the entire solenoid valve harness assembly is defective and will have to be discarded.
Accordingly, it is an object to provide a solenoid valve harness that is easier to manufacture and which is more reliable.